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[Comparable evaluation of serological diagnostic tests (ELISA, IFA and PA methods) for the detection of anti-Borrelia burgdorferi antibody].

We have evaluated the usefulness of the enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody assay (IFA) and particle agglutination (PA) method as serological screening tests for Lyme-borreliosis. Serum samples obtained from two patients with Lyme-borreliosis showed marked high antibody titers for Borrelia burgdorferi when measured by these methods. Of the serum of 368 healthy members of the Self-Defense Force in north-eastern Japan screened for the antibody to B. burgdorferi, 8.4%, 3.7%, 4.6% were found positive by the ELISA, IFA, and PA method, respectively. However, Western blot analysis of these "positive" sera demonstrated no identical bands to those seen in the serum from the patients with Lyme-borreliosis. While 85% and 15% of Treponema pallidum hemagglutination test (TPHA)-positive sera (20 samples) showed a false-positive reaction by the ELISA and IFA method, respectively, no cross-reaction to the anti-B. burgdorferi antibody was observed in these sera by the PA method. The analysis of the serum of the patients with autoimmune diseases (rheumatoid arthritis; 11 cases, systemic lupus erythematosus; 46 cases) by the ELISA and PA methods resulted in a cross-reaction to some extent, which suggested that the antibodies produced by autoimmune mechanisms such as the anticardiolipin antibody can cause a cross-reaction to the anti-B. burgdorferi antibody. These findings indicate that the PA and ELISA rather than the IFA method should be recommended for rapid and conventional screening of Lyme-borreliosis and that serum "positive" for the anti-B. burgdorferi antibody determined by these tests should be confirmed by Western blot analysis to negate the cross-reactions.

Agglutination Tests↗

The use of chosen serological diagnostic methods in Lyme disease in horses. Part II. Western blot.

In this investigation the Western blot test was treated as a method verifying results of the IFA, commercial ELISA and standardized ELISA tests (described in Part I). The verifying investigations were performed on 82 serum samples, which in the commercial ELISA were positive in 36 cases, dubious in 31 cases and negative in 15 cases as well as on 5 serum samples obtained from horses infected with Leptospira spp., which in the ELISA commercial were dubious (total of 87 sera samples). The antigens, against which the immunological response in horses was directed, were also established. The Milenia--Blot--Borrelia IgG test (MIDBO IgG-Kit 30 TESTS: DPC Bierman GmbH) was used in the investigation. In view of species differences, rabbit anti-horse IgG (whole molecule) alkaline phosphatase conjugate, no A6063 SIGMA-ALDRICH was used interchangeably. Also the control sera were substituted with the horse control sera. It was demonstrated that the Western blot test is the most reliable in the serological diagnosis of B. burgdorferi infection in horses. The commercial ELISA and standardized ELISA tests represent a lower diagnostic value than the Western blot test, although similar to each other, while the value of the IFA is minimal. In the Western blot test antigens were established against which the immunological response in horses in mostly directed. In the sera evaluated in this test as positive the presence of antibodies, mainly against antigens with the following molecular weights: 41 kDa, 62/60 kDa, 93 kDa, 72 kDa, 34 kDa (OspB), 66 kDa was noted. At the same time, antibodies contained in the sera accepted as negative, in 55.5% cases also reacted with the antigen of 41 kDa. It points to its minimal specificity. On the basis of the results obtained it is recommended that serological examination of horses should be with the ELISA and that positive or dubious results should be verified with the Western blot test.

Animals↗

Acute schistosomiasis mansoni in Finnish hunters visiting Africa: need for appropriate diagnostic serology.

Three symptomatic and 3 asymptomatic patients with acute schistosomiasis mansoni are described. The index case presented with fever and eosinophilia 4-6 weeks after swimming in the Pipi River of the Central African Republic, suggesting acute schistosomiasis (Katayama fever). A fortunate early diagnosis led to early treatment of these schistosomiasis patients. Diagnosis was obtained based on the finding of one Schistosoma mansoni egg in the index case and positive serology in all cases. A commercially available passive haemagglutination test for serum bilharzia antibodies was negative in all cases prior to, and 2 weeks after treatment. However, antibodies against gut-associated antigens (GAA) of adult S. mansoni worms could be demonstrated using the indirect immunofluorescence technique. These cases illustrate the importance of using appropriate diagnostic assays for the early demonstration of infection by schistosomes in previously unexposed "nonimmune" patients with atypical symptoms and in asymptomatic individuals at risk even after brief exposure to schistosome-containing water in endemic countries. Careful (and repeated) stool examination and appropriate serological tests are the keys to prompt diagnosis of S. mansoni infection.

Adult↗

An experimental marker vaccine and accompanying serological diagnostic test both based on envelope glycoprotein E2 of classical swine fever virus (CSFV).

Envelope glycoprotein E2 is the most immunogenic protein of classical swine fever virus (CSFV). In a proposed model of the antigenic structure of E2, the N-terminal half of E2 forms two independent structural antigenic units, A and BC. E2 without transmembrane region (E2-TMR) is expressed and secreted into the medium of insect cells by use of the baculovirus expression system. The immune response induced by E2 protects pigs against CSFV. Recently, we showed that the protective immune response to a homologous CSFV challenge can be induced by a single unit, A or BC, of E2. An indirect blocking ELISA, or complex trapping blocking assay (CTB) based on both units is routinely used worldwide for serological diagnosis of CSFV infections. Here we show that E2-TMR is secreted into the medium as a homodimer. This E2 homodimer was used to develop a CTB detecting antibodies directed against one immunogenic unit of E2. Thus, the protective immune response induced by E2 containing one unit was not detected with a modified CTB based on the other unit, whereas immune responses induced by a variety of low virulent CSFV strains were detected with such a modified CTB. These results indicate that a deletion E2 protein in combination with a modified CTB are feasible as CSF marker vaccine and accompanying differentiating diagnostic test.

Animals↗

[Serological diagnostic trial of the causative virus of Bell's palsy by anti-herpes virus antibodies in the paired sera].

Substantial evidence obtained through polymerase chain reaction techniques strongly supports that reactivation of latently infected herpes simplex virus (HSV) in geniculate ganglia is the main cause of Bell's palsy. However, serum antibody titers to HSV rarely increase in patients with this disease. This discrepancy may result from the difficulty in detecting a small increase in antibody titers by conventional serological analysis. To detect such a small increase in antibody titer, we defined the significant increase in IgG antibody titers more precisely, and examined the association of HSV or varicella-zoster virus (VZV) with Bell's palsy. From 40 patients with Bell's palsy, paired sera were obtained within the 4th disease day and 2 weeks later. IgG antibodies to HSV, VZV, cytomegalovirus (CMV), or measles virus (MsV) were measured with solid-phase enzyme immunoassay (EIA). IgM antibodies were measured with captured EIA. Each antibody titer was expressed as an EIA-value, which was quantitatively measured by using a calibration curve prepared from the samples containing known titers to the virus in proportion to the logarithm of its titer. An EIA-value ratio (EVR) between paired sera and a corrected EVR was calculated according to the formulae: EVR = [EIA-value in the second serum]/[EIA-value in the first serum]; corrected EVR = [EVR to HSV, VZV or CMV]/[EVR to MsV]. The association with a virus was determined to be positive when the corrected EVR of the virus was beyond the normal range (the logarithmical mean +/- 3 SD of corrected EVRs among 24 healthy controls) while the corrected EVR of the other viruses were within it. Using the corrected EVR, 6 patients were positive: 4 for HSV, 2 for VZV. On the other hand, the conventional serological analysis, which confirms positivity by a 4-fold increase in IgG antibody titer or a demonstration of IgM antibody, disclosed only 2 positive patients (1 for HSV, 1 for VZV). EIA is a very sensitive method of detecting antibodies. Corrected EVRs can exclude a decrease in antibody titers induced by corticosteroids, which are generally used for therapy of Bell's palsy. Moreover, the normal range of corrected EVRs can be defined more precisely than in conventional serological analyses. Our results indicate that some sensitive analysis, such as the corrected EVR method, may make it possible to serologically detect the causative virus of Bell's palsy.

Adult↗

Establishment of a statistical base for use of ELISA in diagnostic serology for infectious bovine rhinotracheitis.

The critical statistical parameters of an enzyme-linked immunosorbent assay were determined to enable quantitation of antibody responses in cattle affected with infectious bovine rhinotracheitis. A system of controlling well-to-well variations in optical density reading across a microtitre plate was evolved and dose--response assays were carried out to determine the dilution of serum which gave the greatest discrimination between acute and convalescent sera from an infected animal. Use of a standard serum was studied in further assays. An increase in optical density value of 0.15 was set as a diagnostic criterion for a significantly rising antibody response. This compared well with the conventional criterion of a fourfold rise in virus neutralizing antibody titre.

Animals↗

[Serologic diagnostic of Toxoplasma gondii infections].

The diagnostic of T. gondii infection is one of the most interesting features of the disease for investigators, since parasitological diagnostic is difficult to reach in the early period of the infection. The diagnostic is exclusively based in the detection of serum specific antibodies (IgG, IgM, IgA, IgE) and more recently, in the avidity of serum IgG. No matter the high specificity and sensitivity of the test used for diagnostic, one test sample is not enough to inform us about the antibody type as a parameter for early or late period of infection.

Animals↗

[Serological diagnostic studies of the occurrence of coronavirus infections in cattle with respiratory diseases].

Of paired serum samples of 196 cattle with respiratory disease from 37 herds which were tested for hemagglutination inhibiting antibodies against coronavirus (BCV) 185 of the first specimens and 190 of the second ones gave positive results. This difference was due to five animals of five different farms showing seroconversions between the time of the blood collections. A significant rise in antibody titer (no less than 4-fold) was evident in 28 cattle from 3 of the above mentioned and 12 other farms. Altogether serological indication of acute coronavirus infections were gained in 33 (16.8%) of animals with respiratory diseases which derived from 17 of 37 herds. Most of these infections (about 35%) occurred in animals older than 6 months while calves up to 3 or 6 months were only affected in a ratio of ca. 10%, respectively.

Animals↗

Microbiological and serological diagnostic tests for Helicobacter pylori: an overview.

Different invasive and non-invasive diagnostic tests are available for the diagnosis of H. pylori in the individual patient. In practice, endoscopic tests are best for a primary diagnosis of H. pylori infection because endoscopy allows assessment of treatment indications. The new rapid urease tests may help the clinician in treatment decision-making. Culture is currently not recommended for routine evaluation, but it is becoming increasingly important in certain populations with higher prevalence of drug resistance, since it allows testing for susceptibility to antibiotics. Serological testing has been recommended for initial pre-endoscopy or pre-treatment screening in dyspeptic patients. However, several current 'in-office' tests appear insufficiently accurate or would need further validation before being recommended for use in clinical management strategies at a primary care level. The urea breath tests are best suited to confirm eradication early after treatment, while laboratory serology tests are of limited use, since 6 months are required before a result can be obtained. The serological office tests cannot be used for post-treatment assessment of H. pylori status.

Bacteriological Techniques↗

Microbiological and serological diagnostic tests for Helicobacter pylori: an overview.

Different invasive and non-invasive diagnostic tests are available for the diagnosis of H. pylori in the individual patient. In practice, endoscopic tests are best for a primary diagnosis of H. pylori infection because endoscopy allows assessment of treatment indications. The new rapid urease tests may help the clinician in treatment decision-making. Culture is currently not recommended for routine evaluation, but it is becoming increasingly important in certain populations with higher prevalence of drug resistance, since it allows to test for susceptibility to antibiotics. Serological testing has been recommended for initial pre-endoscopy or pre-treatment screening in dyspeptic patients. However, several current "in-office" tests appear insufficiently accurate or would need further validation before being recommended for use in clinical management strategies at a primary care level. The urea breath tests are best suited to confirm eradication early after treatment while laboratory serology tests are of limited use since 6 months are required before a result can be obtained. The serological office tests cannot be used for post-treatment assessment of H. pylori status.

Bacteriological Techniques↗

Evaluation of cellular and serological diagnostic tests for the detection of Mycobacterium bovis-infected goats.

We have evaluated the comparative intradermal skin (CID) test, the interferon gamma (IFN-gamma) assay, two ELISAs with bovine PPD antigen, the standard and the anamnestic using sera obtained, respectively, at the time of the tuberculin injection and 15 days later, for the diagnosis of caprine tuberculosis (TB). The sensitivity and specificity results were high for the CID test (83.7%, 100%), the IFN-gamma assay (83.7%, 96%) and the anamnestic ELISA (88.6%, 95.8%). In contrast, they were comparatively low for the standard ELISA (54.9%, 88%). However, test results with the standard ELISA were positive in a group of goats with cavitating TB (100%). A combination of the CID test and the IFN-gamma assay offered the highest sensitivity, 95.8%, and also high specificity, 96%. In spite of this, the evidence that the serological tests were most sensitive for the detection of goats with severe lesions (100% positivity) suggested that a combination of CID test and anamnestic ELISA may be most useful as part of an eradication campaign against caprine TB.

Animals↗